Stoker



J. B. EHQLCM l amb 24', ESM.

STOKER Original Filed Jan.

STOKER 2 Sheets-Sheet.

Original Filed Jan. 50- 1928 rammed Masas, laat i' l 1,797,721

'i `v TNT OFFICE JOHN B. EHRLICH, OF PORTLAND, OREGON f STOKER 011gina1 application tiled January 30, 1928, lSerial No. 250,518. Divided and this application led February 20, 1929. lSerial No. 341,551.

Thisapplication is a division of the applin wall `83 extends across the boiler a short-discants co-pending application Serial No. tance from the rear wall 84. The relation, 250,518. shape and size of these elements will vary This invention relates generally to stokconsiderably with different installations. ers for burning cut fuel, and particularly to The device itself consists of two main ele- 55 a special form of' stoker adaptable to indusments. namely especial form of grate and an trial purposes. airjpreheating device. The grate includes a 'lhe Erst object of' this invention is to propaii` of hollow side frames 85 which are vide astoker which will secure the most complaced close to the side walls 80 of the boiler 1U plete combustion possible.. v which are supported at theirl rearward ends 60 The second object is to adapt the stoker to in the bridge wall 83 and at their forward all kinds of solid fuel in cut or crushed form. ends in the boiler front 80, the front being rl`he third object is to provide a stoker havsomewhat higher than the rear. Midway ing a special forni of self-cooling grate bar, between the side frames 85 is a U-shaped and having means for varying the path of center frame 87 in which is mounted a pluo5 i the burning gases from the'time `they are rality of sprocket wheels 88 having round generated until the vtime they pass beyond Ahubs 80 which journal in the frame 87, which the gratos. n., p I hubs have square extensions 90 formed The fourth object is to provide a grate thereonwhich fit into square openings in the whose individual units are rotatable with re-l grate bars47. The opposite end of each bar v70 lation to each other and are so arranged as 47 is mountedfon the-r square end 91 of the to cause an undulating motion to the fuel as trunnion 92 of the cam 93 upon which rides it passes over the gratos. an arm 94 of the cover .plate 95 which serves The fifth ob]ect 1s to so constI'uCt the as a closure for the open top side of the frame grates of the stoker that'air passing through 85, 75

same shall be warmed and distributed in a The frames 85 are also provided with air manner to provide a flow of air to the Vilroutlet openings 96 at the lower portion thereous grate areas best adapted for 601111119766 of which discharge air beneath the under side combustion of the fuel. of the grate bars 47. The sprockets 88 also gri These. and other objects, will become more have formed thereon the cam surfaces 97 upon se apparent from the specification following as which `ride the arms 98 which Support the illustrated in the accompanying drawings, in double sloping angle bar 99 which form a which: closure for the top side of the frame 87.

Figure 1 is a longitudinal section through In front 0f the furnace is placed a motor n form of the device aS. applied t0 im ndus 100 from which is driven a blower 101 which' @13113011012 FLUT@ 2,13 a fragmentlry Sec' delivers air through the duct 102 into the tion taken along the l1ne`2-2 in Figure 3. manifold 103 over the bridaewau 83 From Figli@ 3 is n Section take? along the une 3"*3 the manifold 103 extend banches 104 which m Il ligure l' Flgure 4 1S an amalfi-ed frag' connect with the'rearmo'st ends ofthe frames o mentar-y section taken along therline 10-1O 85 d 87h f hhh t d f in Figure l. Figure 5 is a section taken along .thealllnanifodmleglscn leleurd :$120132 the line 5#5 in Figure 3.

Similar numbers' of reference refer to simiy Combustion Chamb??? elliher thrugh the grate bar openmgse, or in reversing direclar parts throughout the several views. Y Referring in detail to the drawings, there tions from' the frames 85 0T 87 BY that 1S is illustrated a common form of boiler havmeant that the Cams are so timed that when ingr the tubes 'T9-"at whose forward end is themembe 99 SUP (as ShOWH 111 lgulegl positioned the` boiler front of 'brickworln then the members 95am down, and vice versa., in which is Vformed a tire door opening 81 thereby securing repeated reversals in the v5o and an ash pitdoor opening 82. A bridge direction of flow of air across the grates. 150

It is of course understood that the members 95 and 99 may be sectional (as shown in Figure 1) and that only enough of the arms 94 and 98 are needed to properly operate same. v

Fuel is supplied to the device from a magazine 105 which is hinged on a pivot 106 on the front 107 of the boiler. A door 108 is provided at the outlet of the fuel magazine for controlling the supply of fuel to the grat-es. It is of courseobvious that fuel may be supplied to the magazine 105 by a chute 109, or in any other convenient manner.` Rotation is supplied to the grate bars 47 by means' ofa chain 110 which is driven from a reduction gear 111, and, in turn, through the sprocket wheel 112 on the countershaft 113, which sprocket wheel drives the chain 114 around the idler sprocket wheels 115 and the various sprocket wheels 88 of the grate bars 47. Each grate bar 47 is provided with openings 48 in the flat sides thereof and has a plurality of encircling flanges 49 disposed along the length of each bar in alternate fashionthat is, the flanges of one bar will be intermediate to the flanges of the adjacent bars.

It will be noted that fuel is admitted to the 'combustion zone in a relatively flat layer which moves along the grates in undulating or wave-like form, due to the fact that the hexagonal grate bars 47 are alternately positioned so that the corners of one set of bars .are up while the flat sides of the intermediate ,bars are up, thereby not only providing a continuous feed of fuel through the furnace, but also providing a thorough and constant agitation for the fuel.

In addition to this ideal condition for fuel feeding it will be seen that there is also provided a means for preheating the air used in the combustion, which air is also used to protect the grate bars 47 from over-heating.

In the ordinary form of chain grate a given section of metal remains exposed to the cold throughout its travel along the top side of the grate and cools olf on the under side. Obviously, the time during which it is' exposed to heat is often sufficient to bring about the destruction of the grate. `Whereas in the device herein described the portion of the grate exposed to the heat is constantly being turned away therefrom and air is permitted to flow through.A the hollow grates, thereby further protecting same.

In the type of furnace shown herein there is a constant reversal in the air flow affected by means of the members 95 and 99,` one instant flowing toward the center of the furnace and the vnext instant flowing toward the other sides thereof, thereby securing a complete mixing of the gases and uniform distribution of the heat developed within the combustion chamber. Obviously, the supply of air delivered to the combustion can be easily controlled at the blower 101, and the amount of fuel consumed can be controlled by the position of the door 108.

I am aware that many forms of furnaces have been constructed for industrial purposes; it is therefore not my intention to cover such devices broadly, but I do intend to cover all such forms and modifications thereof as fall fairlywithin the appended claims.

I claim:

1. In a Stoker the combination of a pair of spaced hollow side frames with a plurality of rolling grate bars rotatably mounted between said side frames, each of said bars having an air passage formed therethrough connecting with the interior of said side frames, each of said side frames having a cover plate over the top thereof forming a closure for the top side of its side frame, and means for alternately raising and lowering said cover plates 'in opposite directions for the purpose of reversing the path of the burning gases as they pass over said grates.

2. A stoker for industrial furnaces consisting of a pair 'of hollow side frames disposed against opposite walls of a furnace setting, an intermediate frame between said side frames, said frames sloping downwardly away from the point of fuel feeding, a plu rality of rotatable hollow grates having polygonal surfaces provided with air outlets communicating with vthe interior thereof, means for rotating all of said grates in the same direction, an air supplying manifold communicating with each of said side frames, fan means for supplying air to said manifold, each of said side framesand intermediate frame having an air outlet along its outer side, a cover plate over each of said outlets forming a closure therefor adapted to deflect air laterally across said grates when partially raised, means for rotating all of said grates in a manner to carry fuel thereon downwardly along theirsloping surface, and means for raising and lowering said cover plates successively in opposite directions in a manner that the flow of air along said grates from said frames shall be continually reversed.

3, A stoker for furnaces having a plurality of hollow rotatable grate bars forming a sloping grate area, an air-conducting frame supporting the ends of said bars having an outlet along the top side thereof through which air can escape laterally across said grates, a closure for each of said openings, and means for operating said closures alternately in a manner to successively reverse the flow of air across said grates.

JOHN B. EHRLICH. 

